The Slippery Rock Gorge Trail, part of the New York-to-North Dakota North Country National Scenic Trail, extends from Hells Hollow to Eckert Bridge. A number of geologic features occur all along the trail. Those within Hells Hollow are described here.

The first part of the Slippery Rock Gorge Trail coincides with the Hells Hollow Trail, or parallels it across Hell Run. The geologic features along this part are the same as for the Hells Hollow Trail.

After the Slippery Rock Trail leaves the bank of Hell Run and enters a tributary hollow, it passes the entrance of another long abandoned coal mine. Where the trail crosses the stream, note the confluence of the orange stained stream flowing from the old mine (from the left looking upstream) versus the other stream. Again, the caved mine entrance is marked by the gray shale waste piles.

Abandoned Coal Mine

Acid Mine Drainage

The trail then returns to the rim of Hells Hollow, where it passes well above Hells Hollow Falls, then into another tributary valley. As the trail follows the east side of this second tributary valley back towards Hells Hollow, you may notice cobbles and boulders of igneous and metamorphic rocks. These rocks, called erratics, are foreign to the bedrock in this area. They were glacially transported here from Canada.

When the trail once again reaches the rim of Hells Hollow, look to the right of the trail. Notice the natural bridge made of Vanport Limestone.

A little further along, the trail encounters another natural Vanport Limestone bridge. This time, the trail actually crosses over the natural bridge.

First Natural Bridge

Second natural Bridge

The last location of geological significance to note in the Hells Hollow portion of the Slippery Rock Gorge Trail is a short distance beyond the second natural bridge. Again, the trail passes over a natural bridge. This time, water is flowing under the bridge. The stream may be seen emerging from a small cave to the north (left) of the trail, passes under the trail and bridge, and emerges in a small waterfall on the other side. The inside of the cave exhibits scalloped walls, which are common in caves. A number of Vanport Limestone outcrops are present along the trail in this area. Some have the walking fern on them, which anchors the tip of its leaf to the limestone, and releases the other end. It then repeats the process and "walks" across the outcrop. I'm not sure where it's going or what it does when it reaches the end of the outcrop.

Third Natural Bridge

Cave

From here, the trail continues down Hells Hollow to its confluence with Slippery Rock Creek. The trail continues upstream along Slippery Rock Creek, sometime along the stream, sometimes along the rim or in side hollows. It passes many outcrops of various rock units, landslide areas, and flat areas of glacial outwash. It ends at Eckert bridge, where the North Country Trail continues along the Kildoo Trail to McConnells Mill and Alpha Falls.